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O. R. TREFZ. MUPFLING ATTACHMENT FOR UPRIGHT PIANOS.

No. 476,842. Patented June 14, 1892.

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OTTO R. TREFZ, OF PHILADELPHIA,

PATENT OFFICE.

PENNSYLVANIA, ASSIGNOR TO THE LESTER PIANO COMPANY, OF SAME PLACE.

MUFFLING ATTACHMENT FOR UPRIGHT PIANOS.

SPECIFICATION forming part of Letters Patent No. 476,842, dated June 14, 1892.

.Application filed March 9, 1892.

To a/ZZ whom t may concern:

Be it known that I, OTTO R. TREFZ, a citizen of the United States, residing at the city of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Muiifiing Attachments for Upright Pianos, of which the following is a specification.

My invention has relation in general to muiiling attachments for pianos, and more particularly to mechanism for shifting the muiiing device or curtain into and out of action.

The principal objects of lny invention are, first, to provide an efficient and comparatively inexpensive muliiing attachment for upright pianos, whereby sound may be deadened or muiiied without in any wise aecting the action of the instrument; second, to provide simple, durable, and compact mechanism accessible from the keyboard for shifting the muiiling device or curtain into and out of operative position; third, to provide such mechanism with means for automatically retaining the mufliin g device and its accessories in both operative and inoperative positions.

My invention consists of a movable mufiing device provided with a curtain adapted for insertion between the hammers and wires, an operating-rod for said device, a bell-crank lever connected with said rod, a pivotal handlever accessible from the keyboard, and a link connecting the bell-crank and hand-levers.

My invention further consists of a movable muiilin g device provided with a curtain adapted for insertion between the hammers and wires, an operating-rod for said device, a bellcrank lever connected with said rod, a pivotal hand-lever accessible from the keyboard, a link connecting the bell-crank and handlevers, and a spring-and-knuckle bearing for automatically retaining the muiiiing device in operative or inoperative position.

My inventionfurtherconsists of theimprovements hereinafter described and claimed.

The nature and objects of my present invention will be more fully understood from the following description, taken in connection with the accompanying drawings, forming part hereof, and in which Serial No. 424,277. (No model.)

Figure l is a front view of so much of the interior ot an upright piano as is necessary to illustrate a mull'ling device embodying features of my invention in application thereto; and Fig. 2 is a side view of the vright-hand end of Fig. l,illustrating in full lines the position of the parts of the mechanism' of the inuftling device when the latter is in operative position and showing` in dotted lines the position of the parts when the muiiling device is in inoperative position.

In the drawings, c is a portion of the respective end walls of the case of an upright piano.

a are the strings, c2 are the hammers, and a3 are the keys.

ZJ is a muflier-bar provided with a curtain or apron b', adapted for insertion between the hammers c2 and strings a in order to deaden or niuflle the sound of the piano. In the present instance this muffler-barb is carried by the free ends of a twin pair of rockerarms c, pivotally connected with the respective end walls of the piano-case. However, this bar b may be supported in any preferred manner that will afford it a sufficient range of motion to permit of the insertion or withdrawal of the curtain b from between the hammers d2 and strings a.

l is an operating-rod, connected at its upper extremity with one of the rocker-arms c and at its lower extremity with a bell-crank lever c, pivotally connected with one of the end walls of the case.

f is a hand-lever pivotally connected at f with the end wall of the case c and provided at the upper end with a hand-knob f2, aecessible from the keyboard to the hand of the pianist.

g is a link pivotally connected at one extremity to the bell-crank lever e and at the other extremity to the hand-lever f.

s is a spring secured at one end to the casing and having its tree extremity in engagement with a knuckle h, formed at the lower end of the hand-lever f.

Vhen it is desired to muflie the sound of the piano-for example, when the pianist is practicingr and wishes to avoid annoying others-the hand-lever fis pushed by the pian- IOO ist into the position shown in full lines in Fig. 2. This movement of the hand-leverf causes the link g, bell-crank lever e, and rod d to shift the muliler-bar b into position for permitting the apron or curtain b to occupy a position between the-strings a and hammers c2, so that the latter impinge upon or against the apron b instead of against the strings c', whereby the sound of the piano is diminished or muffled without in any wise interfering with the action of the instrument. The apron b may be shifted out of range of the hammers a2 by pushing the leverf in the reverse direction, whereupon the full sound or tone of the piano is restored. In either case the spring s contacts with one of the operative faces of the knuckle-bearing 7L, and thus automatically maintains the parts in the required position until they are again shifted by the hand of the pianist.

Having thus described the nature and ob jects of my invention, what I claim as new, and desire to secure by Letters Patent., is-

l. The combination, in a muiiiing attachment for upright pianos, of a curtain or apron adapted for insertion between the hammers and Wires, link-work for operatingr said curtain or apron, a pivotal hand-lever having one extremity accessible from the keyboard and the other extremity provided with a knuckle and attached to said link-work, and a spring for engaging said knuckle, substantially as and for the purposes set forth.

2. The combination, in a mufiling attachment for upright pianos, of a curtain or apron adapted for insertion between thehamlners and wires, link-work for operating said curtain or apron, a pivotal hand-lever having one extremity connected with said link-work and the other extremity accessible from the keyboard, and a spring-and-knuckle bearing for automatically retaining the curtain or apron in operative or inoperative position, substantially as and for the purposes set forth.

In witness whereof I have hereunto set my signature in the presence of two subscribing witnesses.

OT"O R. TREFZ.

Witnesses:

RICHARD C. MAXWELL, HERMANN BORMANN. 

